Wire cloth supporting and attaching means



Sept. 24, 1935. ||l R, RAF-TON 2,015,087

WIRE CLOTH SUPPORTING AND ATTAGHING MEANS Filed Nov. 5, 1952 3 Sheets-Sheet l /0 l Z/ /9 .#750v /9 Z/ Sept. 24, 1935. l H. R' RAFTON 2,015,087

WIRE CLOTH SUPPORTING AND ATTACHING MEANS Filed Nov. 5, 1932 3 Sheets-Sheet 2 Sept. 24, 1935. H. R. RAFTON WIRE CLOTH SUPPORTING AND ATTACHING MEANS Filed NOV. 3, 1932 3 ISheets-Sheet 5 @i f mm,

Patented Sept. 24, 1935 PATENT OFFICE WIRE CLOTH SUPPORTING AND ATTACHING MEANS Harold Robert Rafton, Andover, Mass., assigner to Rafton Engineering Corporation, a corporation of Massachusetts Application November 3, 1932, Serial No. 641,056

12 Claims.

This invention concerns means for supporting or attaching wire cloth. y

The principal object of this invention is to provide means for supporting or attaching relatively delicate wire screen cloth, particularly that of fine mesh.

An important object is to provide means for supporting or attaching ultra wire cloth.

A further object is to provide an elastic and flexible edging for fine mesh wire cloth.

A further object is to provide a rubber edging for wire cloth.

A further object is to provide a novel form of resilient supporting means for wire cloth commonly employed for screening purposes.

Other objects and advantages of my invention will become apparent during the course of the following description.

In the drawings I have shown several embodiments of the invention. In this showing,

Figure 1 is a plan View of a screen and associated elements adapted for use, for example, with a gyratory screening mechanism,

Figure 2 is a section on line 2-2 of Figure 1,

Figure 3 is a plan view of a modified form of circular screen,

Figure 4 is a section on line 4 4 of Figure 3,.

Figure 5 is a plan View of a further modied form of circular screen,

Figure 6 is a section on line 6-6 of Figure 5,

Figure 7 is a plan view of a rectangular screen structure,

Figure 8 is a section on line 8-8 oi' Figure 7,

Figure 9 is a view similar to Figure 7 showing a slightly modified form of rectangular screen,

Figure 10 is a section on line Ill- I0 of Figure 9,`

Figure 11 is a, fragmentary plan view showing an edge portion of a circular screen showing means ior assisting in bonding the screen to the attaching means therefor,

Figure 12 is a similar view showing a modied form of screen for a similar purpose,

Figure 13 is a sectional view through a screen showing the edges of the screen distorted for the same purpose,

Figure 14 is a plan view of a circular screen structure showing the screen elements secured against one face of the attaching ring,

Figure 15 is a section on line I5-i5 of Figure14,

Figure 16 is a similar view showing a modied form of attaching ring,

,va-"Figure 1'? is a plan view showing a modified form ot resilient supporting means,

Figure 18 is a section on line |8-I8 of Figure 17,

Figure 19 is a sectional view showing one means for mounting and supporting a circular screen cloth, 5

Figure 20 is a similar View showing a modified' form of means for connecting a rectangular screen to the supporting means therefor,

Figure 21 is a plan view of the screen assembly shown in Figure 20, l0 Figure 21A is a plan view showing 9, type of separable fasenjng,

Figure 21B is a section on line 2IB of Figure 21A,

Figure 21C is a section similar to 2IB showing l5 a modied form of fastening,

Figure 22 is a detail section showing a modified form of mounting for the screen including covering means for the attaching device,

Figure 23 1s a similar View showing the modi- 20 ed form of covering means for an attaching device,

Figure 24 is an enlarged detail sectional View showing means at one edge of the screen for securing it tothe supporting means therefor, 25

Figure 25 is a sectional view of the screen structure of Figure 24 mounted in operative position in a peripheral launder pan,

Figure 26 is a plan View of a circular screen showing the closure device or connecting means 30 when a substantially flat assembly is employed, and,

Figure 27 is a sectional view showing the use of a closure or attaching means for securing the screen cloth in position with respect to a cylindrical supporting frame.

In the screening art, a number of commercial vibrating screens are known which employ cloth of substantially rectangular shape, and other screens such as gyratory riddles are known which employ cloth of substantially circular shape. In order to use wire cloth on such machines it is necessary to attach it usually along its periphery to some sort of support.

In the case of the cloths of substantially rectangular shape it is customary to attach them to suitable supporting means either along the entire periphery, or along two opposite sides, whereas with cloths of circular shape it is customary to attach them .around the entire periphery. Likewise in certain screens. attachments are also made at other points on the cloth surface. For example, in the vibrating screens a central attachment parallel to two of the sides of the wire cloth is sometimes made, whereas in gyratory riddles with cloths of circular formation an attachment is'sometimes made at the center of the cloth.

Inanycasetheclothisusuallyattachedto a substantiallyrrigid framework sometimes of wood, but usually of metal. The cloth is sometimes fastened by ysuitable means such as nails, screws, bolts, snaps, or the like to such framework. and sometimes a top clamping means is provided so that the edge of the cloth -is yheld substantially firmly clamped between clamping members.

Also, especially when using the nner mesh cloths, there is sometimes provided a supporting backing member suitably foraminous either of perforated metal or'of relatively coarse wire cloth sometimes rolled, which serves to support the nner mesh cloth and also in certain cases to provide a medium against which the finer cloth may strike when vibrating.

'I'he method of attachment for wire cloth detailed above has proven satisfactory for relatively coarser mesh cloths. But when it has been attempted to employ this method for the attachment of very ne mesh cloth, and especially ultra wire cloth made by plating fine mesh cloths such as is described in my copending application Serial No. 420,794, filed January 13, 1930, considerable difficulty has been experienced. It has been foamd that with ordinary methods of attachment, such cloths tore either at the periphery at or near the points of attachment, or split somewhere in the central area after a very short usage, and examination of the cloth indicated that the destruction of the cloth was not due to the wearing of the wire meshes but rather-to some strain placed upon the cloth which was too great for the cloth to withstand.

Rubber gaskets, both soft and hard, were placed between the clamping supports and the wire cloth in an endeavor to provide a cushion for the edges of the cloth, but these proved to be of no substantial help in preventing the destruction of the cloth long before it would have been worn out by the wear caused by any passage of material therethrough. Ihe experiments above were carried out both with and without various kinds of backing means for the ne mesh wire cloth. In fact it appeared at that time that vibratory and gyratory screens were not suitable for the attachment of such line mesh cloth and that the vibratory and gyratory action in itself was the cause of cloth destruction rather than any inherent dimculty in the attachment of the cloth.

However careful analysis of the situation and subsequent experiments proved this viewV to be incorrect, and means have now been devised whereby wire cloth of very fine mesh and extremely tenuous and fragile nature can be attached successfully to vibratory or gyratory screening frames and be caused to yield full life, that is, with the present invention the cloth now wears out owing to passage of material through the meshes rather than to any splitting or tearing. It has thus been proved that' the gyratory or vibratory motions did not of themselves destroy such cloth, but rather the hitherto imperfect methods ci attachment of the cloth to the gyratory or vibratory screens.

As will be apparent, such a supporting or attaching means as is herein disclosed, will prove to be of considerable economic importance as the hitherto desirable very fine mesh and ultra eiotbscildbeusedonlyatconsiderableexpene in commercial screening machines owing to their extremely short life because of ripping and tearing. By themeanshereindisclosedtheuseof such cloths is thus made much more feasible for moderate cost commercial screening and their life compares favorably with the life of other wire cloths of coarser mesh used on the screening of like material. v

The means which have been found to accomplish this result are what may be termed free floating means. The present invention provides elastic means which is attached'to the periphery of a wire cloth and serves for attachment of the cloth to a supporting frame. Thus preferably a soft rubber edging is attached to the cloth and the edging itself is then attached to' the supporting means. This is not to be confused with the use of a rubber gasket or gaskets between .the clamping means, and between which the cloth is inserted for support, or the attachment of 2o such gasket or gaskets permanently to the cloth itself. In such formerly known means the clamping pressure of the clamping means was transferred through the more or less resilient gaskets to the periphery of the wire cloth itself. In the present invention, however, there is no clamping pressure put directly on the wire cloth, there existing between the clamping means and the edge of the wire cloth an area of greater or lesser extent comprising flexible and elastic 3o material. This material is itself secured at one edge by the clamping means and at the other edge is attached tothe wire cloth but there is a free area of the elastic material between the clamping means and the embedded or attached 3a edge of the wire cloth. The wire cloth may thus be said to be free floating, that is, it is connected with the screen frame only through a flexible and elastic med-lum.

One specinc embodiment of my invention is o illustrated in Figures l and 2 wherein the numeral Il designates a circular wire cloth such as is commonly employed as a screening element in a gyratory riddle. 'Ihe peripheral portion of the cloth is attached to an annular ring H preferably formed of soft sheet rubber, and the outer periphery of the rubber ring is adapted to be attached to suitable supporting means carried by the screening apparatus. It will be apparent that the means of attachment of the rubber ring are spaced from the outer periphery of the cloth Il, and accordingly there exists between the edge of the wire cloth and the supporting means a free area. which serves to distribute the sudden strains and shocks of a commercial screening apparatus and to prevent ripping or tearing of the fragile wire cloth.

A suitable method of manufacturing such a free floating rubber edge cloth follows. It will be illustrated using actual dimensions of wire cloths and attached rubber edging rings 4which have been successfully employed commercially in the practice of the present invention.

A circle of ne mesh wire cloth orultra wire cloth 19" in diameter is provided. Uncured rub- 65 ber sheeting approximately thick is shrunk on a hot plate. Two pieces of about eleven point bristol board are procured and on each of these are drawn circles corresponding to the interior and exterior diameters oi' the annular rubber 70 rings desired for attachment to the periphery of the cloth. In the present instance 18" is the diameter of the inner circle and 221/2" is the diameter of the exterior circle. The unmarked sidesofthesetwopiecesofbristolboardaxetheno -order to cause adhesion.

sponged with naphtha and placed each upon a sheet of the rubber sheeting described above, said sheet being just previously sponged with naphtha on the side of contact. Each rubber sheet is then firmly attached to its bristol board by rolling on the surface of the bristol board with a squ'eegee roller. Continuous cuts are then made along the previously marked circles on the bristol boards, cutting through the bristol board andrubber. After remo'val of the central and exterior portions, there remain two annular rings of sheet rubber, each attached on one surface to a similar annular ring of bristol board. The purpose of attachment of the bristol board is for ease of handling in the subsequent manipulations. The periphery of the wire cloth to a sufficient depth is then cleaned with naphtha. It is then painted with several coats of suitable rubber cement. The exposed surfaces of the rubber 'rings are also treated with severalcoats of cement. One ring is then' placed rubber side down on a metal table concentrically with the wire cloth and thereabove and pressed firmly thereon in A roller is used for this purpose, which is manipulated circularly upon the bristol board covered surface of the annular ring. This provides a l/2 annular attachment of the peripheral edge of the wire cloth to* the inner edge of the annular rubber ring. The whole is then turned over, and the other rubber ring applied similarly to the other side of the wire cloth and rolled down carefully in order to squeeze out all air bubbles and make a substantially perfect bond between the rubber and the edge of the wire cloth as well as between the two layers of rubber. The assembly is then cured the proper length of time in a dry heat vulcanizer. After the vulcanization has been completed thebristol board is removed from the rubber. The final product is thus a ne mesh or ultra wire cloth, the periphery of which is embedded in an approximately eighth inch thick4 annular ring' of rubber to the depth of 1/2, the free rubber ring extending radially 1% beyond the edge o f the embedded wire cloth, 'Ihis provides sufficient room for attachment of the outer periphery of the annular rubber ring to any suitable support and also for an intermediate area of free rubber which imparts the free floating fe'ature to the wire cloth.

As will be apparent it is desirable with certain cloths of rectangular shape to apply such free floating rubber edging only to two opposite edges, and it is thus to be understood that the invention may be practiced by the attachment of such free floating edging either to the entire periphery of a wire cloth or only to sections of the periphery, or if desired only to spaced points onthe periphery.

It will also be apparent that in the event there is a central attaching point, such as mentioned above in certain gyratory riddles, there may be' provided a central portion of free floating rubber at the center of the Wire cloth. This may be prepared for attachment similarly to the rubber edging described above, except in this case there will be a central disc of free floating rubber attached at its periphery to the inner edge of a central hole in the wire cloth. Such a construction is illustrated in Figures 3 and 4 wherein a circular wire cloth I2 has its peripheral edge connected to a rubber ring I3 similar to the ring II previously described. The wire cloth is provided with a central opening Il and a free floating rubber or similar disk I5 is attached to the portions of the cloth surrounding the opening I4.

An optional arrangement is shown in Figures 5 and 6 wherein a wire cloth I6 has its outer A.

edge portion connected to a rubber or similar ring I1 and the opening I4 previously described is eliminated. A small rubber disk I8 is arranged centrally of the cloth and has its peripheral portion attached to the wire cloth as shown in Figure 6. The center of the rubberdisk I8 is free from the cloth I6 and is adapted to be attached'to a central supporting means.

Similar supporting means may be provided for wire cloths of different types. For example, the wire cloth shown in Figure 7 is m'ade up of a pair of sections I9 having their adjacent edges spaced and connected by a rubber or similar insert 20 whereby the sections I9 are resiliently connected to each other. The remote edges'of the sections I 9 are embedded in or otherwise connected to rubber or other resilient attachment strips 2l. It will be apparent that the outer edges of these strips are arrangeda substantial distance outwardly of the cloth sections IS to permit them to be connected to suitable attaching means with a free area of rubber between the attaching means and the adjacent edges of the cloth sections I9 whereby such sections will be resiliently supported.

A somewhat similar arrangement is shown in Figure 9 except that a single cloth sheet 22 is employed and is connected at opposite edges to resilient attaching strips 23 similar to the strips 2l previously described. A free floating central attaching strip 24, also preferably formed of rubber, has its opposite edge portions connected to the-sheet 22 and its central portion free from the cloth sheet to permit it to be connected to suitable attaching means.

It will be apparent of course that with certain screening devices, adapted for cloths of either circular or rectangular shape, particularly those devices which are substantially free from vibration or motion at the point of attachment to the cloth periphery, but which impart motion to the cloth centrally thereof, that the peripheral free floating edging of the cloth may be omitted, and only the central free floating portion be employed.

It has been found in practice, especially when screening strongly alkaline liquid suspensions through rubber edged wire cloths, that it is necessary to secure a very good bond between the metal and the rubber edging so that the bond will have a life equal to that of the wire cloth. This bond has been improved in some cases by perforating with small holes that portion of the wire cloth near its periphery which is to be embedded in the rubber edging. Inordernottobreak the wire strands when perforating, a small needle shape punch may be used which acts to separate the strands rather than to break them, although if the holes are large enough, of course som'e of the strands will be broken. The object of so perforating the edge of the cloth is so that the two annular pieces of rubber placed on the periphery of the cloth will contact through these perforations and make a more perfect bond than they do through the much smaller actualmeshes of the wire cloth itself. Such an expedient is illustrated in Figure 11 wherein a portion of a circular wire cloth 25 is illustrated with openings 26 arranged slightly inwardly of the pe- 'asA ripheryofthesheetand throughwhichthe rubber is adapted to bond.

Other expedients may be employed for improving the bonding of the cloth to the rubber suchasthemeansshowninlilgure 12. Insuch form of the invention, a wire cloth 2l is provided with a row of stitching 2l which may be in the form of a wire thread interwoven with the wire cloth 21. If desired, the method shown in Figure 13 may be employed wherein the wire cloth is roughened at its edges as at Il, for example, by distorting the ends of the wires of the cloth outwardly from their normal positions to permit them to be more readily embedded in the rubber fins rt'n to be understood that me method of at,- taching rubber edging to wire cloth herein described while being my preferred method, is

theclothtotheedgin'gmaybeusedsuchas stitching or the like'.

It is apparent that although desirable, .it is not necessary vto have originally doubleannular rubber ring as ldescribed which serves to embed the edge of the. cloth therebetween, as the wire cloth at its periphery may be attached on one sm'face to a circular ring of rubber'or the like as illustrated in Figures 14 and 15 wherein a wire cloth Ii has its peripheral portion attached to a rubber supporting ring I2 against the upper face thereof. v 4.

Likewise it is apparent that rubber or rubber like material is not the only material possible for use. For example a metallic free Boating edge itself may be made, for example, according to the bellows principle, as illustrated inFlgure 16 and designated by the numeral Il. The inner and outer edge portions of such attachment strip are fiat and the inner edge is adapted to be sol'- dered or otherwise secured to the wire cloth 34. 'Ihe outer edge of the attaching strip may be clamped or otherwise connected to the screening apparatus. In Figures 17 and 18 a circular screen II is illustrated and preferabLv is provided at its edge with a reinforcing strip 36 which may be a strip of rubber bonded to the wire cloth.

A plurality of radial coil springs 31 have their inner ends secured to the screen by passing through the strip It, which strip serves to reinforce the wire and prevent the inner ends of the springs from pulling through the wire fabric. The other ends of the springs may be suitably suptzorted with respect to the screening appara Also material other than rubber or metal may be used such as fabric or the like but such material usually suffers from lack of desired elasticity, and I donot consider either metal or fabric to :tao convenient or desirable as is the rubber edg- Also there may be fabric inserts, reenforcements, or the like in the rubber ring itself but these again I do not consider a preferred modification in my invention as they tend to reduce the desired elasticity of the annular ring. However they may be advantageously used in certain cases for insertion in the outer part of the ring, a free that one device which may=be employed is that s of clamping between two annular clamps similar in cross-sectional shape to those ordinarily used on vibrating screens using cloths of rectangular shape. As shown in Figure 19, the numerals il and Is designate upper and lower annular clamping rings having parallel flanges. The screen structure illustrated in Figure 1 is shown as having its resilient ring Il arranged with its outer edge portion between the flanges of the clamping rings 3l and t9 and secured in pontion by l5 bolts 40. Obviously there is a space between the inner edges of the clamping rings and the outer edge ori the wire cloth il.

Another method of attaching free floating wire cloth is by means of a closure device or separable 20 fastener such as those made of a series of interlocking members disposed along two companion lines or strips. of which there are several types on the market. These are closed and released by tha action of .a sliding member engaging both strips and capable of being pulled therebetween lsuch as the zipper, talon, or similar type. In

such case the wire cloth may be attached to the edge of one of the companion closure strips. suitably by rubber, and a second edging suitably of rubber (although other material may be used) may be conveniently attached to the other companion closure strip, this second edging being suitable f r attachment to a screen frame. One such com lete closure may be provided for each side of a wire cloth to be attached to the screen frame when a rectangular wire cloth is employed. For example, such an arrangement is shown in Figures 20 and 21 in which a rectangular wire cloth 4l has opposite edge portions embedded in 40 or otherwise secured to parallel rubber or other strips Il'. Parallel resilient supporting strips l2 have their outer edges arranged between upper and lower pairs of parallel clamps 4I and u. The adjacent edges of the strips Il and l2 are 45 cnnected by a separable fastener I5 of the character referred to, and it will be apparent that the operation of the pull member associated with each separable fastener is adapted to connect the strips 4i to the strips 42 or to disconnect them 50. therefrom. This construction provides an extremely simple and quick method of reclothing commercial screening machines.

In the case of rectangular screens, some device usually is employed for stretching the cloth taut, and the elastic edging of the present invention takes up the inequalities of such stretching and thus it will be apparent that a perfectly smooth screening area will be presented to the material screened, without involving any substantially unequal stresses of the wire cloth itself. Such an arrangement is shown in Figure 20 wherein a turn buckle is threaded on the adjacent ends' of axially alined rods 4l, the outer ends of these rods being connected to the lower clamping frames by nuts 4I.

' If a liquid tight joint is required at the closures or le fasteners, rubber flaps adapted to 'be arranged thereover and conveniently snapped 70 to the frame, or metal sheaths, may be used. Such an arrangement is illustrated in Figure 22, wherein the wire cloth 49 is illustrated as having a rubber or similar strip SII carried by one edge thereof, although it will be apparent that the 76 construction may be duplicated at opposite edges of the cloth where rectangular cloth ls employed, while the strip 50 and associated parts will be annular in shape when employed in connection with a circular cloth. The strip A5l) is provided with an integral flap 5l having its outer portion substantially U-shaped as at 52v to receive the upstanding flange of the uppermost frame of a pair 53. The elements referred to are of the type previously described, as will be apparent, and the outer edge portion of the flap 5I is provided with a snap fastener 54 to adapt it for detachable connection tothe vertical flange of the upper clamp 53. A separable fastener 55 connects the outer edge of the strip 50 to a resilient strip 56 arranged between the clamping members and secured in position with respect thereto by bolts or other fastening elements 51.

In Figure 23, the cloth 58 is attached at its edge to the resilient strip 59 which is connected to an outer resilient strip 60 by a separable fastener 6I. This fastener is provided with a metal sheathing strip 62 to provide a leak-proof joint at the line of connection between the strips 59 and 60.

The modifications of the invention wherein the closure means or separable fasteners are employed in connection with rectangular wire cloths also may be practiced using only one closure, in which case one rubber edging of 'a cloth may be attached to the screen frame and the other edging may be equipped with one of the companion closure strips, the other of which may be attached to a rubber edging which is engaged by the other side of the supporting frame.

For attaching wire cloths of circular shape such as to gyratory riddles, ordinary clamping means may be used such as is shown in the screen pan disclosed in my copending application 359,943, filed May 2, 1929. However with this method of attachment it is at times difficult to get a perfectly taut Wire cloth so that anotherv method has been devised which is shown in Figure 24, and which satisfactorily provides for the stretching feature. A rubber covered grid 63 such as is disclosed in my copending application 510,268, filed January 21, 1931, is attached around its periphery to a series of flat head stove bolts 64 which in turn pass through an annular steel ring 65. The rubber edging 66 of the Wire cloth 61 is suitably perforated along a circle with the proper numberof holes, and then the rubber edged cloth itself is attached to this circle of stove bolts by slipping the holes in the-rubber edging over the extending bolts. Over this edging may then be placed an annular ring 68 which serves as a dam in the flnalassembly. The whole` is then attached to a peripheral launder pan as is shown in my application 359,943, filed May 2, 1929, the entire assembly being shown herein in Figure 25.

Another method of attaching a circular rubber edged cloth is by means of a detachable clobe utilized also for supporting a wire cloth with respect to the surface of a cylindrical supporting frame. Referring to Figure 27 the numeral 14 designates a cylindrical support having its upper end flared outwardly as at 'l5 and then turned inwardly to form an annular horizontal flange 16. The circular cloth 'Il is connected at its edge to an annular flexible ring 18, and the outer edge portion of this ring is adapted'to fit over the upper end of the support. A detachable connector i9 is adapted to connect the ring or strip i8 to an annular strip 80 surrounding the support and attached thereto.

Another type of separable fastener which may suitably be employed, particularly with rectangular cloths, is one in which the mutual members of the connecting strips do not interlock, but rather are held together by a rod of metal, rawhide or the like. This modification is illustrated in Figures 21A and 21B. It may comprise a series of U shaped loops 4l and 42 the alternate loops being secured respectively in the edging 43 and I4', and being engaged by a removablerod 45. Instead of U shaped loops, as will be apparent, hooked projections may be used as indicated by 46' and 41 in Figure 21C.

From the above description it will be seen that my free floating screen is of novel and unique design, and of great utility. Of course the examples given are to be taken purely as illustrative and in no way as limiting, as it will be understood that the construction of the free floating screen may be practiced with a number of variations, while still maintaining the principle of attaching the wire cloth in such a manner so that it will not rip or tear in use. Ihe flexibility and resiliency of the supporting means absorbs shocks incident to loading the screening cloths and operating the screening devices,and accordingly the use of very fine mesh cloth has been rendered practicable, and this is especially true of ultra wire cloth made by plating fine mesh cloths, as described in my copending application Serial No. 420,794 referred to above. Such ultra wire cloths, in view of the present invention, now may be freely used and last for a substantial length of time without ripping or tearing. In this connection it will be noted that with a gyratory screening apparatus the flexibility and/ or resiliency of the means connecting the screening element to the support serves to prevent the transmission of destructive gyratory shocks to the screening element,while the flexibilityand/or resiliency of the connecting means transversely of the plane of the screening element absorbs shocks incident to the weight and movement of material on the screening element and incident to the loading of material'thereon. In other words, the flexibility and/or resiliency involved in the construction efficiently absorbs any shocks to which the material of the screening element ordinarily is subjected and which ordinarily cause premature destruction of the screenlng element.

Where in the claims I use the word rubber, I mean to include not only rubber, but also rubberlike material, rubber substitutes, and similar materials, provided that they possess a substantial degree of flexibility and elasticity.

As previously stated, the present invention is intended for use with vibratory or gyratory screening devices, or more generally speaking, with a screening device wherein relatively rapid but restricted movement takes place. Accordingly, where the term vibratory screening device has been employed in the claims, it is understood that this term is intended to cover screeningl devices of the general type indicated, and is not intended to limit the use of the invention to a vibratory screening device.

It is to be understood that the forms of the invention herewith shown and described are to be taken as preferred examples of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope oi the subjoined claims.

I claim:

1. In a vibratory screening device, a substantially planiform screening element, an attachment therefor spaced from the screening area oi" sai'd screening element and elastic means ilexibLv connected to said screening element with extension therebeyond, said extension forming the sole connection between said attachment and an edge portion of said screening element, said screening element terminating in spaced relation to said attachment and relatively movable with respect thereto.

2. In a vibratory screening device, a substantially planiform screening element, an attachment therefor spaced from the screening area of said screening element, and elastic means ilexibly connected to said screening element with extension therebeyond, said extension forming the sole connection between said attachment and an edge portion of said screening element and possessing a substantial degree of universal elasticity, said `screening element terminating in spaced relation to said attachment and relatively movable universally with respect thereto.

3. In a vibratory screening device, a substantially planiform screening element, attaching means for said screening element at one edge portion thereof, an attachment for the opposite edge portion of said screening element spaced from the screening area of said screening element, and elastic means iiexibly connected to said screening lelement with extension therebeyond, said extension forming the sole connection be- I tween said attachment and the last named edge portion of said screening element, said screening element having its last named edge portion spaced from said attachment and relatively movable with respect thereto.

4. In a vibratory screening device, a substantially planiform screening element, an attachment therefor spaced from the screening area of said screening element, and spaced elastic means flexibly connected to said screening element each with extension therebeyond, said extensions forming the sole connection between said attachment and edge portions of said screening element, said edge portions of said screening element being spaced from said attachment whereby said screening element is bodily movable with respect to said attachment. Y

5. In a vibratory screening device, a substantially rectangular substantially planiform screening element, attaching means for opposite edge portions of said screening element spaced from the screening area of said screening element, and elongated elastic means ilexibly connected to said screening element with extensions therebeyond, said extensions forming the sole connection between said opposite edge portions of said screening element andl said attaching means,

. said opposite edge portions of said screening element being spaced from said attaching means whereby said screening element is bodily movable f with respect to said attaching means.

6. In a vibratory screening device, a substantially circular substantially planiform screening element, an attachment, and an elastic ring connected at its inner edge to the outer edge of said screening element and at its outer edge to said a attachment and forming the sole connection between said screening element and said attachment, the edge of said screening element being spaced from the connection of said elastic ring with said attachment whereby said screening element is bodily movable with respect to said attachment.

'7. In a vibratory screening device, a substantially circular substantially planiform screening element, an attachment, an elastic ring connected at its inner edge to the outer edge of said screening element and at its outer edge to said attachment and forming the sole connection between said screening element and said attachment, the edge of said screening element being spaced from the connection of said elastic ring with said attachment whereby said screening element is bodily movable with respect to said attachment, and an elastic element connected solely at its edge portions to said screening element substantially centrally thereof.

8. In a vibratory screening device, a substantially planiform screening element, an attachment, and an elongated rubber strip having an edge portion of said screening element embedded in one edge portion thereof, the otheredge portionof said strip being secured to said attachment and spaced from said edge portion of said screening element, said strip forming the sole connection between said attachment and said edge portion of said screening element whereby the latter is relatively movable with respect to said attachment.

9. In a vibratory screening device, a substantially circular substantially planiform screening 0 element, an attachment,`and an annular rubber strip having its inner peripheral edge portion secured to the peripheral portion of said screening element and its outer peripheral portion spaced from and secured to said attachment on a substantially circular line, said strip forming the sole connection between said attachment and said screening element whereby the latter is bodily movable with respect to said attachment.

10. In a vibratory screening device, a substantially planiform screening element, an attachment therefor, said screening element and said attachment constituting a pair of relatively movable members, means forming the sole connection between said attachment and an edge portion of said screening element, said means comprising two strips having their remote edge portions connected respectively to said edge portion oi said screening element and said attachment, and separable connecting means for the adjacent edge portions of said strips, and means forming the sole connection between an opposite edge portion of said screening element and said attachment consisting of an elastic strip having a free area between said attachment and said 65.

comprising two strips at least one of which is 7l i Iiiy tot

elastic and having their remote edge portions connected respectively to said edge portion of said screening element and said attachment, mutuallyinterlocking members carried by the adjacent 'edge portions of said strips, and a member operable for interlocking said interlocking members with each other, said elastic strip having a free area between the interlocking members thereof and the relatively movable member to which the remote edge of such strip is connected to relatively movably connect said relatively movable members.

12. In a vibratory screening device, a substantially planiform screening element, an attachment therefor, and means forming the sole conf mi tici iii nection between said attachment and an edge portion of said screening element, said means comprising a strip connected at one edge portion to said attachment and an elastic strip connected at one edge portion to an edge portion of said screening element, mutually interlocking members carried by the other edge portions of said strips, and a, member operable for interlocking said interlocking members with each other, said elastic strip having a free area between the interlocking members thereof and said screening element to provide for relative movement between said screening element and said attacnment.

HAROLD ROBERT RAFI'ON. 

